To determine the size of the population when the roommates began recording data, we need to look at the y-axis, which represents the Invasive Species Population, at the point where the curved line intersects the y-axis.
Since the question asks for the population size rounded to the nearest tens and does not provide specific numeric values or the image to reference, we can hypothesize that the intersection point on the y-axis will provide a certain numeric value, say \( P \). You would typically round that value to the nearest ten.
For example, if the population at the point of intersection is 47, it would round to 50. If the population is 29, it would round to 30.
To give a specific answer, you will need to refer to the actual image data to see where the point intersects. Please check the specific intersection point on the graph to provide the accurate rounded population size.